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DYNC1H1 gene
Reviewed by Medicinsk Expert•Last updated: 2026-10-22•Gene

DYNC1H1 gene

The DYNC1H1 gene encodes a heavy chain protein essential for the dynein-dynactin complex, which acts as a cellular transport system for proteins and vesicles.

Normal Function

The DYNC1H1 gene provides instructions for making a protein that is part of a group (complex) of proteins called dynein. This complex is found in the fluid inside cells (cytoplasm). Dynein is turned on (activated) by attaching (binding) to another complex called dynactin. This dynein-dynactin complex binds to various materials within cells. Using energy provided by molecules called ATP, the dynein-dynactin complex moves material along a track-like system of small tubes called microtubules, similar to a conveyer belt.

The dynein-dynactin complex is necessary for protein transport, positioning of cell compartments, movement of structures within the cell, and many other cell processes. Dynein helps neighboring nerve cells (neurons) communicate by transporting sac-like structures called synaptic vesicles that contain chemical messengers. The protein produced from the DYNC1H1 gene is a heavy chain, which forms the core of the dynein complex.

Health Conditions Related to Genetic Changes

Spinal muscular atrophy with lower extremity predominance

At least eight mutations in the DYNC1H1 gene have been found to cause a condition called spinal muscular atrophy with lower extremity predominance (SMA-LED). This condition is characterized by muscle weakness and wasting (atrophy) in the lower limbs that often begins in infancy or childhood. These mutations replace single amino acids in the heavy chain subunit, altering the core of the dynein complex and impairing its function. Decreased synaptic vesicle transport in motor neurons is thought to contribute to the muscle weakness and atrophy.

Other disorders

DYNC1H1 gene mutations have been identified in some people who have intellectual disability. These affected individuals often have a brain malformation called polymicrogyria, where the brain develops too many, unusually small folds. In addition to intellectual disability, some affected individuals develop seizures and movement problems.

Other Names for This Gene

  • cytoplasmic dynein 1 heavy chain 1
  • cytoplasmic dynein heavy chain 1
  • DHC1
  • DHC1a
  • DNCH1
  • Dnchc1
  • DNCL
  • DNECL
  • DYHC
  • DYHC1_HUMAN
  • dynein heavy chain, cytosolic
  • dynein, cytoplasmic 1, heavy chain 1
  • dynein, cytoplasmic, heavy polypeptide 1
  • HL-3
  • p22

Frequently Asked Questions

The condition is generally progressive, meaning muscle weakness and atrophy tend to worsen over time, particularly in the lower extremities. However, the rate of progression can vary among individuals. While respiratory function is less commonly affected than in severe classic SMA, long-term monitoring is essential to manage potential complications such as scoliosis, joint contractures, and fatigue. Early intervention with physical therapy and assistive devices can help maintain mobility and quality of life.
Diagnosis usually begins with a clinical evaluation noting asymmetric muscle weakness, followed by genetic testing. A geneticist may order a targeted gene panel or whole exome sequencing to identify specific mutations in the DYNC1H1 gene. Electromyography (EMG) and nerve conduction studies may also be performed to assess nerve and muscle function, helping to rule out other neuromuscular disorders and confirm the pattern of denervation associated with this condition.
Early signs often include delayed motor milestones, such as difficulty achieving head control or sitting independently. Parents may notice that the infant has significantly weaker legs compared to arms, leading to a "frog-leg" posture or difficulty kicking. As the child grows, there may be a noticeable difference in gait, with frequent tripping or a waddling walk, while upper body strength remains relatively preserved compared to the lower body.
DYNC1H1-related SMA, also known as SMA with lower extremity predominance (SMA-LED), primarily affects the legs, causing weakness and wasting that is significantly more pronounced in the lower limbs than the upper limbs. In contrast, classic SMA caused by SMN1 mutations typically presents with symmetric weakness affecting both the arms and legs, often starting in the trunk and proximal muscles. Additionally, SMA-LED is an autosomal recessive condition linked to defects in intracellular transport, whereas classic SMA is linked to the loss of the survival motor neuron protein.
Source: MedlinePlus, National Library of Medicine

MedlinePlus brings together authoritative health information from the National Library of Medicine (NLM), the National Institutes of Health (NIH), and other government agencies and health-related organizations.

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